ARP Head Stud torque specs needed
08-01-2006, 10:02 PM
#1
ARP Head Stud torque specs needed Engine is a 402 ls2 stroker with ETP Heads, gm ls2 6.0 head gaskets and arp head studs
What are the torque specs? I didn't think they were angle torque ,and 65 lbs doesn't sound enough.
Sequence is the same as ls1 right?
Please help, thanks
What are the torque specs? I didn't think they were angle torque ,and 65 lbs doesn't sound enough.
Sequence is the same as ls1 right?
Please help, thanks
08-02-2006, 12:25 AM
#2
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I'm confused by ARP's instructions as well. If I remember correctly form a previous engine I built which had an iron block and alum heads the 65 ft # made sense because the alum heads would expand considerably more than iron heads but in the case of the LSx engines with alum block and heads I don't understand the rational of the lower 65 ft # torque as both alum parts would expand together. I emailed ARP about clarifying this but have not heard back from them.
Another issue I have with those studs is that they have only 14, 11 x 2 threads which screw into the block. The block has 18 + threads in it, a C5R head stud has 17 threads and a stock head bolt screws into the block about 17 threads. Why did ARP throw away 3 to 4 threads of increased block grip? I'm always concerned about stripping aluminum anyway and that's why I prefer studs but I can't understand giving up those threads in the block.
Another issue I have with those studs is that they have only 14, 11 x 2 threads which screw into the block. The block has 18 + threads in it, a C5R head stud has 17 threads and a stock head bolt screws into the block about 17 threads. Why did ARP throw away 3 to 4 threads of increased block grip? I'm always concerned about stripping aluminum anyway and that's why I prefer studs but I can't understand giving up those threads in the block.
08-03-2006, 06:20 PM
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Originally Posted by roadtrip120
Engine is a 402 ls2 stroker with ETP Heads, gm ls2 6.0 head gaskets and arp head studs
What are the torque specs? I didn't think they were angle torque ,and 65 lbs doesn't sound enough.
Sequence is the same as ls1 right?
Please help, thanks
What are the torque specs? I didn't think they were angle torque ,and 65 lbs doesn't sound enough.
Sequence is the same as ls1 right?
Please help, thanks
If so use this:
First pass 25lbft second pass at 50lbft, and finally a 3rd at 70lbft.
Finally install the 5 smaller ARP bolts and torque them to 22lbft.
If using motor oil use this:
First pass 30lbft second pass at 60lbft, and finally a 3rd at 80lbft.
Finally install the 5 smaller ARP bolts and torque them to 28lbft.
(Incase you didn't know you have to lube the threads and washers before installing... you must use either arp lube or motor oil. )
Install in this order:
01-06-2010, 12:46 AM
#7
Are you using arp moly lube?
If so use this:
First pass 25lbft second pass at 50lbft, and finally a 3rd at 70lbft.
Finally install the 5 smaller ARP bolts and torque them to 22lbft.
If using motor oil use this:
First pass 30lbft second pass at 60lbft, and finally a 3rd at 80lbft.
Finally install the 5 smaller ARP bolts and torque them to 28lbft.
(Incase you didn't know you have to lube the threads and washers before installing... you must use either arp lube or motor oil. )
Install in this order:
If so use this:
First pass 25lbft second pass at 50lbft, and finally a 3rd at 70lbft.
Finally install the 5 smaller ARP bolts and torque them to 22lbft.
If using motor oil use this:
First pass 30lbft second pass at 60lbft, and finally a 3rd at 80lbft.
Finally install the 5 smaller ARP bolts and torque them to 28lbft.
(Incase you didn't know you have to lube the threads and washers before installing... you must use either arp lube or motor oil. )
Install in this order:
When my heads show later this week i'll be installing them on an iron block with cometic gaskets.
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01-06-2010, 04:44 AM
#8
Call ARP. I have an LS1 with studs. The original instructions were for 70 lb-ft on the large studs. The new value is 80 lb-ft. The small studs remain the same. However, I am not sure this applies in your case so call ARP and get the latest guidance.
01-13-2010, 04:54 AM
#10
I got one of their old timers last time I called and he told me that 80 was the new number based on more recent testing but he still used 70. In the end torque wrench accuracy and correct installation is probably more important.There is also a thread in the Gen III Internal section on using the studs, you may want to check that out as well.
01-13-2010, 12:09 PM
#11
Gotta love ARP and their new tech support. I now call three times and hopefully get two answers that are the same I got one of their old timers last time I called and he told me that 80 was the new number based on more recent testing but he still used 70. In the end torque wrench accuracy and correct installation is probably more important.
There is also a thread in the Gen III Internal section on using the studs, you may want to check that out as well.
I got one of their old timers last time I called and he told me that 80 was the new number based on more recent testing but he still used 70. In the end torque wrench accuracy and correct installation is probably more important.There is also a thread in the Gen III Internal section on using the studs, you may want to check that out as well.
01-13-2010, 10:55 PM
#12
Sorry about the inconsistencies, jfyi the torque specs are based on the required clamping force on the head, as well as a percentage of the fatigue limit of the stud. The older 70# rating can still be used and will work just fine for most people, however after speaking with some of the top LSX shootout guys, it has been determined that 70# was not enough clamping force in HIGH horsepower HIGH boost applications. There would be no disadvantages to running the higher torque rating however. I believe fireball and some of the other guys are using even higher torque values than this...
Iron block, Aluminum heads, .045" Cosmetic MLS gasket, ARP 12pt studs. It should make 510-520ish RWHP N/A and was built to hold up to a 400shot(though I plan to only go as far as 200-250). Think I should just leave it alone at 70#?
01-15-2010, 10:25 PM
#13
At 80 FT-LBS you better have an extreamly accurate torque wrench. That is MAX for those studs. With aluminum blocks its really pushing it. Better have all those threads used all the way down to the blind.
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Why not 75#? 
02-21-2012, 02:10 PM
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I have just completed a 2.5 hour tour of the Earnhardt-Childress Racing Engines shop in Welcome, North Carolina.
ECR Engines build a 5.0L naturally-aspirated LS engine for the Daytona Prototype series of road race cars. The engine delivers 600 crankshaft horsepower. The engine uses a Kinsler ITB intake manifold. The sanctioning body limits the engine's rpms to a maximum of 7,100.
During that visit I had a discussion with their R&D Shop Foreman about cylinder head attachment for the LS engines. ECR has determined that the LS heads move around on the engine, even when naturally aspirated, when the cylinder heads are torqued using the method shown above. What they now do using ARP 12mm studs that have been turned down to 11mm outside of the threads that go into the block, is to torque the studs 85 lb-ft. Then they loosen the nuts completely, reapply ARP's thread lube, and retorque the studs to 85 lb-ft. again.
They stated that the retorquing eliminates head movement, and shows a significant improvement in gasket sealing and a more uniform distribution of the clamping load across the gasket. The important thing to take away from the information that ECR Engines provided is - AFTER YOU HAVE COMPLETED YOUR INITIAL TORQUING OF YOUR CYLINDER HEAD STUDS, REMOVE THE NUTS, APPLY A FRESH COATING OF THREAD LUBRICANT - BEING SURE YOU DO NOT GET ANY LUBRICANT BETWEEN THE WASHER AND THE CYLINDER HEAD, AND RETORQUE THE NUT.
ECR has also learned that 95 lb-ft. of torque is superior to 85 lb-ft. But, in order to reach 95 lb-ft. the engine must have cylinder heads with more column strength than the standard LS cylinder heads. In the standard cylinder heads, the fastener column will be crushed at 95 lb-ft. of torque.
ECR Engines build a 5.0L naturally-aspirated LS engine for the Daytona Prototype series of road race cars. The engine delivers 600 crankshaft horsepower. The engine uses a Kinsler ITB intake manifold. The sanctioning body limits the engine's rpms to a maximum of 7,100.
During that visit I had a discussion with their R&D Shop Foreman about cylinder head attachment for the LS engines. ECR has determined that the LS heads move around on the engine, even when naturally aspirated, when the cylinder heads are torqued using the method shown above. What they now do using ARP 12mm studs that have been turned down to 11mm outside of the threads that go into the block, is to torque the studs 85 lb-ft. Then they loosen the nuts completely, reapply ARP's thread lube, and retorque the studs to 85 lb-ft. again.
They stated that the retorquing eliminates head movement, and shows a significant improvement in gasket sealing and a more uniform distribution of the clamping load across the gasket. The important thing to take away from the information that ECR Engines provided is - AFTER YOU HAVE COMPLETED YOUR INITIAL TORQUING OF YOUR CYLINDER HEAD STUDS, REMOVE THE NUTS, APPLY A FRESH COATING OF THREAD LUBRICANT - BEING SURE YOU DO NOT GET ANY LUBRICANT BETWEEN THE WASHER AND THE CYLINDER HEAD, AND RETORQUE THE NUT.
ECR has also learned that 95 lb-ft. of torque is superior to 85 lb-ft. But, in order to reach 95 lb-ft. the engine must have cylinder heads with more column strength than the standard LS cylinder heads. In the standard cylinder heads, the fastener column will be crushed at 95 lb-ft. of torque.
Last edited by Pumba; 02-22-2012 at 12:03 PM.
